Biochemistry and Molecular Biology Concepts, Exams of Advanced Education

Download Biochemistry and Molecular Biology Concepts and more Exams Advanced Education in PDF only on Docsity! MCAT Practice Exam Questions and answers 2023 Thin layer chromatography can use silica plates which are very polar. Will polar or non polar substances have lower Rf values on this plate? - Polar substances - they will have a higher affinity for the silica and thus will not travel as far as the non polar substances A titration of a strong acid with a strong base or vice versa has an equivalence point around what pH? - 7 What type of bond is usually disrupted during denaturation of proteins? - H bond Is uracil a purine or pyrimidine? - Pyrimidine (A is a purine, so must be paired with a pyrimidine, also U replaces T, and T is a pyrimidine) Are peptide bonds highly reactive? - NO, they are very stable (T/F): Bomb calorimetery is a good way to determine bond enthalpies within a compound. - FALSE - would need a ton of info What is the approximate pKa of COOH, NH3+? - 2; 9 What would happen if dideoxynucleotides were omitted from a replication mixture? - DNA polymerase would replicate the entire copy of DNA and produce copies of all the same length - gel electrophoresis would reveal one large band Total pressure = __ + __ - Atmospheric pressure + gauge pressure Conditions of extreme starvation result in a high level of __. - Cortisol As non-polar protein groups cluster in water, water has a (increase/decrease) in entropy. - Increase - more water molecules are free now that they don't have to solvate each individual molecule of protein On the lac operon, the repressor binds to the __. - Operator - to prevent RNA polymerase from binding What charge do basic amino acids have at pH 7.4? - + What makes group I and II introns different from non-grouped introns? - They are SELF- SPLICING i.e. they do not have splicing proteins to help them When an action potential induces a muscle contraction, Ca2+ is released into the __. - Cytosol (not the sarcoplasmic reticulum) Are the particles released by gamma decay charged? What does this mean for their movement in electric fields and magnetic fields? - No - gamma decay releases photons which are uncharged; uncharged molecules do not move in electric fields or magnetic fields How do beta particles behave in electric and magnetic fields? - Beta decay releases electrons - negatively charged particles are deflected by electric and magnetic fields Does blood flow faster through capillaries or arteries? Why? - Blood flows faster through arteries - capillaries have a greater NET cross-sectional area Which has higher BP: systemic or pulmonary circulation? Explain why. - Systemic has a higher BP - pulmonary circulation is shorter than systemic, which means it has less resistance (formula), and the right ventricle generates less force (to pulmonary circulation) than the left ventricle does (to systemic circulation). Since P = F/A and pulmonary has lower force and area, pressure in pulmonary must be lower than systemic. Which has a higher blood flow rate (BFR): pulmonary or systemic circulation? - They are equal because they are connected in series How does inhalation facilitate venous flow into the right atrium? - Because during inhalation, thoracic pressure decreases (diaphragm pushes down and expands thoracic cavity), which causes blood to flow from high to low pressure (from veins into right atrium) - this is negative pressure breathing Which way do positive charges migrate towards in an electric field: towards the anode or cathode? - Cathode What are anomers? - Diastereomers of cyclic sugars (the SAME sugar, i.e. dif forms of (ex) glucose) - differ configurations at the anomeric carbon (alpha (down) or beta (up) position of the OH group) Switching from one anomer to another is called (rotamutation/mutarotation). - Mutarotation (rotamutation does not exist) Counterclockwise is (R/S) absolute configuration. - S configuration What is the difference between d-/l- and D-/L- notation? What about +/- notation? - Lowercase letters are for optical activity (as are + and -; + is the same as d, - is the same as l); uppercase letters are just for configuration Which method of therapy focuses on self-actualization and helping patients become more fulfilled? - Humanist When someone supports an idea and reads something that has both opinions of their idea (supportive and against), are they more or less likely to support that idea once they have read it? - More likely - belief perseverance What are demand characteristics? - Circumstances in which participants in a study guess the researchers' hypothesis and modify their behavior to fulfill that hypothesis Dizziness and poor balance are indicative of a problem with what part of the inner ear? - Semi- circular canals (cochlea is for pitch and intensity of sounds) Attention-seeking behavior is indicative of what social disorder? - Borderline personality disorder At what point in the demographic transition model is population lowest? - At the very beginning since throughout the transition population is always increasing Anger or dissatisfaction based on inequality is known as __ theory. - Conflict Adding a resistor in parallel (increases/decreases) the overall resistance of the circuit. - Decreases (1/Req = 1/R1 + 1/R2) Whereas resistors in series increase overall resistance Blood pressure is equal to the total cardiac output times what value? - Total peripheral resistance What parts of the body are unlikely to show up on MRI scans? - MRI subjects hydrogen ions to a magnetic field and in response the ions emit radiation - so tissues that contain low H+ ions will not show up on the scan (tissues that do not contain a lot of water, like bones) An electron donor is analogous to a Lewis (acid/base). - Base (same as a Bronsted-Lowry acid which "donates" H+) BUT THEY ARE NOT THE SAME THING - BL acids donate an H+, and Lewis bases donate electrons; a lewis base is not a BL acid because an H+ ion does not have any electrons to donate! What is the difference between standard state and standard conditions? - Standard state is 25C, 1 atm, 1 M; standard conditions (STP) is 0C, 1 atm, and 1 mol of ideal gas occupies 22.4 L What color light has the lowest frequency and energy? - Red (increases as go along ROYGBIV) But red has highest WAVELENGTH A carboxylase uses __ as a reactant. - CO2 A __ mutation results in a premature stop codon. - Nonsense Which carries mitochondrial DNA: egg or sperm? - Egg - sperm contains no organelles (except in tail, but tail is not involved in penetrating egg) During exercise, blood vessels in active muscle (constrict/dilate). - Dilate - to supply more O2 But vessels outside active muscle constrict __ are mental shortcuts. - Heuristics What part of the CNS is responsible for voluntary movements? - Cerebrum What is the Yerkes Dodson law? - Will perform better at simple, skilled tasks when viewed by others, but worse at complex tasks What role do the prefrontal cortex and amygdala have in aggression? - Prefrontal cortex reduces aggression through complex thinking; amygdala heightens aggression by instilling fear How does the phase diagram for water differ from all other substances? - The solid-liquid line has a negative slope, instead of a positive slope Why is RNA more unstable than DNA? - They have an exposed 2' OH group that is susceptible to alkaline hydrolysis (T/F): Some RNAs have more than 4 types of bases. - TRUE - tRNA has modified bases, like inosine Saponification is the hydrolysis of a __ with a base. - Ester How do competitive inhibitors affect Km, Vmax, and kcat? What about non-competitive inhibitors? Mixed inhibitors? Uncompetitive inhibitors? - Competitive inhibitors decrease the affinity of the enzyme for the substrate due to competition, therefore Km increases. Vmax is unaffected and therefore so is kcat Non-competitive inhibitors (bind E somewhere besides active site) decrease Vmax (and thus kcat) while having no effect on Km Mixed inhibitors decrease Vmax (and thus kcat) while either increasing or decreasing Km for the inhibited enzyme Uncompetitive inhibitors (bind ES complex) decrease Vmax (and thus kcat) while decreasing Km for the inhibited enzyme **All decrease Vmax except for competitive (Depolarization/hyperpolarization) stimulates cone cells. This triggers (depolarization/hyperpolarization) of bipolar cells. - Hyper polarization; depolarization What determines if something has a low retention time in gas chromatography? - It has a low boiling point (it is very volatile) What kind of hormone is aldosterone? - Steroid (behaves like testosterone so it is small and hydrophobic - can diffuse into cells) Summarize the hormones secreted by the adrenal glands. - Medulla - epinephrine; cortex - cortisol, aldosterone, low levels of sex hormones The __ triggers skeletal muscle contractions, but the __ coordinates it. - Cerebrum; cerebellum Atmospheric pressure (increases/decreases) with increasing altitude. - Decreases Prokaryotes use what enzyme to uncoil DNA? What about eukaryotes? - DNA gyrase; topoisomerases In a cross between two double heterozygotes, the expected phenotypic ratio for if the genes are UNLINKED is __. - 9:3:3:1 Order of Freud's stages... - Oral, anal, phallic, latency During fight or flight, pupils (dilate/constrict). - Dilate Differentiate between the Schachter-SInger, Cannon-Bard, and James-Lange theories for emotional and physiological/cognitive response. - The Schachter-Singer theory says that emotional experience is determined by one's physiological state and the cognitive interpretation of that state. The Cannon-Bard theory focuses on the central role of the hypothalamus in regulating emotions and is less specifically concerned with physiological activation and cognition (the experience of the emotion and the physiological arousal that accompanies that emotion are experienced simultaneously and independently of each other). The James-Lange theory asserts that emotional experience is primarily based on physiological arousal, and that each different physiological state is associated with an emotion.